Human-derived stem cells such as embryonic stem cells (ES cells) and induced pluripotent stem cells (iPS cells) have an ability to differentiate into many kinds of cells (pluripotency), and application thereof in the field of drug discovery and the field of medicine has been anticipated. A differentiation efficiency in differentiation induction from the stem cells into desired cells is largely dependent on the state of the stem cells as starting materials. That is, the efficiency of differentiation induction is lowered, unless the stem cells maintain pluripotency and keep an undifferentiated state. Thus, quality control of the stem cells is extremely important for industrial application of the stem cells, and the stem cells need to be monitored and their states need to be noninvasively determined.
It is known that in an undifferentiated state, the ES cells produce adenosine triphosphate (ATP) anaerobically by using the glycolytic system. When the cells are differentiated, ATP is mainly supplied by oxidative phosphorylation using the citric acid cycle (TCA cycle) (Non-Patent Literature 1). It is known that the dependency of the ES cells on glucose is higher than that of the differentiated cells, and the ES cells contain glycogen in their cytoplasm (Non-Patent Literature 2).
As a method for detecting glycogen, Periodic acid Schiff staining (PAS staining) is known (for example, Non-Patent Literature 2). In addition, Non-Patent Literature 3 reports quantifying glycogen content in cytoplasm of ES cells through Raman spectroscopic imaging.